Solid storage media systems have been developed for ammonia storage in reductant delivery systems for selective catalytic reduction (SCR). The solid storage media systems typically provide a source of ammonia that is released as needed and delivered to an exhaust gas to treat emissions in an SCR aftertreatment system.
Ammonia provide certain advantages over a urea based system for SCR aftertreatment systems. Ammonia can be delivered successfully at much lower exhaust temperatures, without requiring temperature sufficient to rapidly evaporate and break down the urea. Additionally, the time delay between ammonia injection and available reductant at the SCR catalyst is minimal, making the dynamics and control of the system simpler and more stable. An example ammonia delivery system includes a solid medium storing the ammonia, and a release mechanism for the ammonia, for example through desorption from a medium and/or through a chemical reaction releasing ammonia as a product.
Ammonia delivery systems require the handling and management of gas phase fluids in the ammonia delivery system. Leakage of ammonia gas or other reductants into the environment is desired to be avoided. Therefore, technological developments in the detection and mitigation of gaseous reductant leaks are desirable in this area.